Drug interactions
Fedratinib + Promethazine
Severity: Moderate
Fedratinib and Promethazine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Fedratinib inhibits CYP2D6 and can raise exposure to CYP2D6 substrates. Promethazine is partly metabolized by CYP2D6, so levels and adverse effects such as sedation and QT effects may increase.
What this interaction means in plain words
Fedratinib and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Fedratinib belongs to Oncology; Promethazine belongs to Respiratory.
Why it happens
Inhibition of CYP2D6-mediated metabolism of promethazine by fedratinib.
What to do
Monitor for increased sedation and anticholinergic or cardiac effects and reduce the promethazine dose if they occur.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Other interactions of Fedratinib
- Fedratinib + Thioridazine Contraindicated
- Amobarbital + Fedratinib Major
- Apalutamide + Fedratinib Major
- Brexpiprazole + Fedratinib Major
- Carbamazepine + Fedratinib Major
- Chloramphenicol + Fedratinib Major
Frequently asked questions
Can I take Fedratinib with Promethazine?
MediHelp rates the interaction as moderate. Fedratinib and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Fedratinib inhibits CYP2D6 and can raise exposure to CYP2D6 substrates. Promethazine is partly metabolized by CYP2D6, so levels and adverse effects such as sedation and QT effects may increase.
How serious is the interaction between Fedratinib and Promethazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for increased sedation and anticholinergic or cardiac effects and reduce the promethazine dose if they occur.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.
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